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Structural changes lead to an increase in the number of dairy cows and dry sows kept per group. This has consequences in how easily a farmer can supervise his herd and may be detrimental to animal welfare, specifically regarding social relations, time budget and area of residence. An automated tracking system can support the farmer in his management activities and can provide the foundation for a scientific assessment of the welfare consequences of large groups. In this study, a relatively simple and inexpensive real time location system (RTLS) was developed with the aim of achieving precise localization of several tags (animals) in real time and in a real barn environment. The RTLS was based on the ultra-wideband (UWB) technology provided by DecaWave and was adapted for a time difference of arrival (TDoA) procedure to estimate the tags’ positions. The RTLS can handle up to a hundred tags simultaneously using a Pure ALOHA random access method at 1-second intervals. The localization of the tags was estimated in 2D on a given fixed height using a constrained Gauss-Newton algorithm to increase accuracy and stability. The performance of the overall system was evaluated in two different dairy barns. To determine the precision of the system, static and dynamic positions measured at withers height of a cow (1.5 m) and closer to the ground mimicking a lying cow were compared with a reference system (theodolite). The 2D deviations between the systems were used as a measure of precision. In addition, the scalability in respect to the number of tags and the size of the observed area was examined in situations with ten tags and the situation with 100 tags was simulated with a ten-fold increase in sampling rate. According to the field test, the system as developed can be used for the individual localization of animals. At withers height, most of the measured locations deviated less than 0.5 m from the localizations as measured by the theodolite. At lower heights, and closer to t

Structural changes lead to an increase in the number of dairy cows and dry sows kept per group. This has consequences in how easily a farmer can supervise his herd and may be detrimental to animal welfare, specifically regarding social relations, time budget and area of residence. An automated tracking system can support the farmer in his management activities and can provide the foundation for a scientific assessment of the welfare consequences of large groups. In this study, a relatively simple and inexpensive real time location system (RTLS) was developed with the aim of achieving precise localization of several tags (animals) in real time and in a real barn environment. The RTLS was based on the ultra-wideband (UWB) technology provided by DecaWave and was adapted for a time difference of arrival (TDoA) procedure to estimate the tags’ positions. The RTLS can handle up to a hundred tags simultaneously using a Pure ALOHA random access method at 1-second intervals. The localization of the tags was estimated in 2D on a given fixed height using a constrained Gauss-Newton algorithm to increase accuracy and stability. The performance of the overall system was evaluated in two different dairy barns. To determine the precision of the system, static and dynamic positions measured at withers height of a cow (1.5 m) and closer to the ground mimicking a lying cow were compared with a reference system (theodolite). The 2D deviations between the systems were used as a measure of precision. In addition, the scalability in respect to the number of tags and the size of the observed area was examined in situations with ten tags and the situation with 100 tags was simulated with a ten-fold increase in sampling rate. According to the field test, the system as developed can be used for the individual localization of animals. At withers height, most of the measured locations deviated less than 0.5 m from the localizations as measured by the theodolite. At lower heights, and closer to t

Electronic Support Measures (ESM) systems have many operational challenges while locating radar emitter’s position around irregular terrains such as islands due to multipath scattering. To overcome these challenges, this paper addresses exploiting multipath scattering in passive localization of radar emitters around irregular terrains. The idea is based on the use of multipath scattered signals as virtual sensor through Geographical Information System (GIS). In this way, it is presented that single receiver (ESM receiver) passive localization can be achieved for radar emitters. The study is initiated with estimating candidate multipath scattering centers over irregular terrain. To do this, ESM receivers’ Angle of Arrival (AOA) and Time of Arrival (TOA) information are required for directly received radar pulses along with multipath scattered pulses. The problem then turns out to be multiple-sensor localization problem for which Time Difference of Arrival (TDOA)-based techniques can easily be applied. However, there is high degree of uncertainty in location of candidate multipath scattering centers as the multipath scattering involves diffuse components over irregular terrain. Apparently, this causes large localization errors in TDOA. To reduce this error, a reliability based weighting method is proposed. Simulation results regarding with a simplified 3D model is also presented.

Electronic Support Measures (ESM) systems have many operational challenges while locating radar emitter’s position around irregular terrains such as islands due to multipath scattering. To overcome these challenges, this paper addresses exploiting multipath scattering in passive localization of radar emitters around irregular terrains. The idea is based on the use of multipath scattered signals as virtual sensor through Geographical Information System (GIS). In this way, it is presented that single receiver (ESM receiver) passive localization can be achieved for radar emitters. The study is initiated with estimating candidate multipath scattering centers over irregular terrain. To do this, ESM receivers’ Angle of Arrival (AOA) and Time of Arrival (TOA) information are required for directly received radar pulses along with multipath scattered pulses. The problem then turns out to be multiple-sensor localization problem for which Time Difference of Arrival (TDOA)-based techniques can easily be applied. However, there is high degree of uncertainty in location of candidate multipath scattering centers as the multipath scattering involves diffuse components over irregular terrain. Apparently, this causes large localization errors in TDOA. To reduce this error, a reliability based weighting method is proposed. Simulation results regarding with a simplified 3D model is also presented.

At present, indoor localization system based on ultra wideband(UWB) has attracted more and more attention. In UWB system, Time Difference of Arrival (TDOA) and Two-Way Ranging (TWR) are widely used. However, TDOA requires high-accuracy time synchronization between all anchor nodes and even slight noise can cause large localization error. In TWR localization scheme, although two-way communication between anchor nodes and blind nodes can avoid the time synchronization issue effectively, the clock drift and the number of blind nodes will affect the system performance. To overcome these problems, a new synchronizationfree TDOA location algorithm is proposed. Firstly,the clock model is established and the influence of antenna delay is considered. Then, the system signal exchange mechanism and localization model are proposed. In the system, the blind nodes just receive the ranging signals from anchor nodes so that the system has no limit on the number of blind nodes. Finally,the major factor affecting the accuracy of ranging - clock drift, is discussed, and then a clock frequency offset compensation algorithm is proposed. The indoor localization experiment results show that the indoor localization system designed in this paper can achieve 3-D localization.

Electronic Support Measures (ESM) systems have many operational challenges while locating radar emitter’s position around irregular terrains such as islands due to multipath scattering. To overcome these challenges, this paper addresses exploiting multipath scattering in passive localization of radar emitters around irregular terrains. The idea is based on the use of multipath scattered signals as virtual sensor through Geographical Information System (GIS). In this way, it is presented that single receiver (ESM receiver) passive localization can be achieved for radar emitters. The study is initiated with estimating candidate multipath scattering centers over irregular terrain. To do this, ESM receivers’ Angle of Arrival (AOA) and Time of Arrival (TOA) information are required for directly received radar pulses along with multipath scattered pulses. The problem then turns out to be multiple-sensor localization problem for which Time Difference of Arrival (TDOA)-based techniques can easily be applied. However, there is high degree of uncertainty in location of candidate multipath scattering centers as the multipath scattering involves diffuse components over irregular terrain. Apparently, this causes large localization errors in TDOA. To reduce this error, a reliability based weighting method is proposed. Simulation results regarding with a simplified 3D model is also presented.

At present, indoor localization system based on ultra wideband(UWB) has attracted more and more attention. In UWB system, Time Difference of Arrival (TDOA) and Two-Way Ranging (TWR) are widely used. However, TDOA requires high-accuracy time synchronization between all anchor nodes and even slight noise can cause large localization error. In TWR localization scheme, although two-way communication between anchor nodes and blind nodes can avoid the time synchronization issue effectively, the clock drift and the number of blind nodes will affect the system performance. To overcome these problems, a new synchronizationfree TDOA location algorithm is proposed. Firstly,the clock model is established and the influence of antenna delay is considered. Then, the system signal exchange mechanism and localization model are proposed. In the system, the blind nodes just receive the ranging signals from anchor nodes so that the system has no limit on the number of blind nodes. Finally,the major factor affecting the accuracy of ranging - clock drift, is discussed, and then a clock frequency offset compensation algorithm is proposed. The indoor localization experiment results show that the indoor localization system designed in this paper can achieve 3-D localization.

Electronic Support Measures (ESM) systems have many operational challenges while locating radar emitter’s position around irregular terrains such as islands due to multipath scattering. To overcome these challenges, this paper addresses exploiting multipath scattering in passive localization of radar emitters around irregular terrains. The idea is based on the use of multipath scattered signals as virtual sensor through Geographical Information System (GIS). In this way, it is presented that single receiver (ESM receiver) passive localization can be achieved for radar emitters. The study is initiated with estimating candidate multipath scattering centers over irregular terrain. To do this, ESM receivers’ Angle of Arrival (AOA) and Time of Arrival (TOA) information are required for directly received radar pulses along with multipath scattered pulses. The problem then turns out to be multiple-sensor localization problem for which Time Difference of Arrival (TDOA)-based techniques can easily be applied. However, there is high degree of uncertainty in location of candidate multipath scattering centers as the multipath scattering involves diffuse components over irregular terrain. Apparently, this causes large localization errors in TDOA. To reduce this error, a reliability based weighting method is proposed. Simulation results regarding with a simplified 3D model is also presented.

At present, indoor localization system based on ultra wideband(UWB) has attracted more and more attention. In UWB system, Time Difference of Arrival (TDOA) and Two-Way Ranging (TWR) are widely used. However, TDOA requires high-accuracy time synchronization between all anchor nodes and even slight noise can cause large localization error. In TWR localization scheme, although two-way communication between anchor nodes and blind nodes can avoid the time synchronization issue effectively, the clock drift and the number of blind nodes will affect the system performance. To overcome these problems, a new synchronizationfree TDOA location algorithm is proposed. Firstly,the clock model is established and the influence of antenna delay is considered. Then, the system signal exchange mechanism and localization model are proposed. In the system, the blind nodes just receive the ranging signals from anchor nodes so that the system has no limit on the number of blind nodes. Finally,the major factor affecting the accuracy of ranging - clock drift, is discussed, and then a clock frequency offset compensation algorithm is proposed. The indoor localization experiment results show that the indoor localization system designed in this paper can achieve 3-D localization.

Distributed radar network systems (DRNS) have been shown to provide significant performance improvement. With the recent development, radar network has become an attractive platform for target tracking. In practice, the netted radars in DRNS are supposed to maximize their transmitting power to achieve better target tracking performance, which may be in contradiction with low probability of intercept (LPI). This paper investigates the problem of adaptive resource scheduling based on time difference of arrival (TDOA) cooperation for target tracking by DRNS consisting of a dedicated radar netting station and multiple netted radars. Firstly, the standard interacting multiple model (IMM) algorithm incorporating extended Kalman filter (EKF) is improved by modifying the Markov transition probability with current measurements. Then, a novel resource scheduling strategy based on TDOA cooperation is presented, in which the LPI perfor¬mance for target tracking in DRNS is improved by optimiz¬ing the radar revisit interval and the transmitted power for a predefined target tracking accuracy. The comparison of the predictive error covariance matrix and the expected error covariance matrix is utilized to control the radar netting station under intermittent-working state with TDOA cooperation. Due to the lack of analytical closed-form expression for receiver operating characteristics (ROC), we utilize several popular information-theoretic criteria, namely, Bhattacharyya distance, Kullback-Leibler (KL) divergence, J-divergence, and mutual information (MI) as the metrics for target detection performance in target tracking process. The resulting optimization problems which are associated with different information-theoretic criteria are unified under a common framework. The non¬linear programming (NP) based genetic algorithm (GA) or else known as NPGA is employed to encounter with the highly nonconvex and nonlinear optimization problems in the framework. Numerical results demonstrate t

Underwater source localization problems are complicated and challenging: a) the sound propagation speed is often unknown and the unpredictable ocean current might lead to the uncertainties of sensor parameters (i.e. position and velocity); b) the underwater acoustic signal travels much slower than the radio one in terrestrial environments, thus resulting into a significantly severe Doppler effect; c) energy-efficient techniques are urgently required and hence in favour of the design with a low computational complexity. Considering these issues, we propose a simple and efficient underwater source localization approach based on time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements, which copes with unknown propagation speed and sensor parameter errors. The proposed method mitigates the impact of the Doppler effect for accurately inferring the source parameters (i.e. position and velocity). The Cramér-Rao lower bounds (CRLBs) for this kind of localization are derived and, moreover, the analytical study shows that our method can yield the performance that is very close to the CRLB, particularly under small noise. The numerical results not only confirm the above conclusions but also show that our method outperforms other competing approaches., Circuits and Systems

Projektpartner: Bundesamt für Lebensmittelsicherheit und Veterinärwesen BLV (EDI), 3003 Bern, Agroscope, Institut für Nutztierwissenschaften, 8356 Ettenhausen, Intellion AG, 9016 St. Gallen, Das Lokalisieren und Tracking von Objekten gewinnt auch für Indoor-Anwendungen immer mehr an Bedeutung. Eine vielversprechende Funktechnologie für echtzeit-basierte Lokalisierungssysteme (RTLS) ist die Ultra-Breitband-Technologie (UWB). Für die Lokalisierung in einem Stall von Agroscope wurde ein auf Time-Difference-of- Arrival (TDoA) basierendes Lokalisierungssystem entwickelt, das gleichzeitig bis zu 100 Tags im Sekundentakt und in Echtzeit lokalisieren kann. Mit TDoA lässt sich ein energie-sparendes und skalierbares RTLS realisieren. Die Tags senden dabei im Sekundentakt zu einem zufällig ausgewählten Zeitpunkt einen ultrakurzen Puls aus, der von vier oder mehr fix installierten und per Kabel miteinander synchronisierten Empfängern empfangen wird. Die Empfänger senden über Kabel die präzise Ankunftszeit an eine zentrale Einheit, wo mit der entwickelten Lokalisierungssoftware aus den Laufzeitunterschieden zu den einzelnen Empfängern die Position des Tags im Raum berechnet und angezeigt wird. In Feldtests konnte mit Verifikationsmessungen gezeigt werden, dass sich unter realen Bedingungen im gesamten Raum von 13m x 23m in 95% eine Lokalisierungsgenauigkeit von besser als 50cm realisieren lässt. Die Kollisionsrate betrug dabei <11%. Das hier entwickelte UWB-basierte Lokalisierungssystem lässt sich auch für das asset-tracking in der Produktion oder Logistik einsetzen.

Distributed radar network systems (DRNS) have been shown to provide significant performance improvement. With the recent development, radar network has become an attractive platform for target tracking. In practice, the netted radars in DRNS are supposed to maximize their transmitting power to achieve better target tracking performance, which may be in contradiction with low probability of intercept (LPI). This paper investigates the problem of adaptive resource scheduling based on time difference of arrival (TDOA) cooperation for target tracking by DRNS consisting of a dedicated radar netting station and multiple netted radars. Firstly, the standard interacting multiple model (IMM) algorithm incorporating extended Kalman filter (EKF) is improved by modifying the Markov transition probability with current measurements. Then, a novel resource scheduling strategy based on TDOA cooperation is presented, in which the LPI perfor¬mance for target tracking in DRNS is improved by optimiz¬ing the radar revisit interval and the transmitted power for a predefined target tracking accuracy. The comparison of the predictive error covariance matrix and the expected error covariance matrix is utilized to control the radar netting station under intermittent-working state with TDOA cooperation. Due to the lack of analytical closed-form expression for receiver operating characteristics (ROC), we utilize several popular information-theoretic criteria, namely, Bhattacharyya distance, Kullback-Leibler (KL) divergence, J-divergence, and mutual information (MI) as the metrics for target detection performance in target tracking process. The resulting optimization problems which are associated with different information-theoretic criteria are unified under a common framework. The non¬linear programming (NP) based genetic algorithm (GA) or else known as NPGA is employed to encounter with the highly nonconvex and nonlinear optimization problems in the framework. Numerical results demonstrate t

Distributed radar network systems (DRNS) have been shown to provide significant performance improvement. With the recent development, radar network has become an attractive platform for target tracking. In practice, the netted radars in DRNS are supposed to maximize their transmitting power to achieve better target tracking performance, which may be in contradiction with low probability of intercept (LPI). This paper investigates the problem of adaptive resource scheduling based on time difference of arrival (TDOA) cooperation for target tracking by DRNS consisting of a dedicated radar netting station and multiple netted radars. Firstly, the standard interacting multiple model (IMM) algorithm incorporating extended Kalman filter (EKF) is improved by modifying the Markov transition probability with current measurements. Then, a novel resource scheduling strategy based on TDOA cooperation is presented, in which the LPI perfor¬mance for target tracking in DRNS is improved by optimiz¬ing the radar revisit interval and the transmitted power for a predefined target tracking accuracy. The comparison of the predictive error covariance matrix and the expected error covariance matrix is utilized to control the radar netting station under intermittent-working state with TDOA cooperation. Due to the lack of analytical closed-form expression for receiver operating characteristics (ROC), we utilize several popular information-theoretic criteria, namely, Bhattacharyya distance, Kullback-Leibler (KL) divergence, J-divergence, and mutual information (MI) as the metrics for target detection performance in target tracking process. The resulting optimization problems which are associated with different information-theoretic criteria are unified under a common framework. The non¬linear programming (NP) based genetic algorithm (GA) or else known as NPGA is employed to encounter with the highly nonconvex and nonlinear optimization problems in the framework. Numerical results demonstrate t

Distributed radar network systems (DRNS) have been shown to provide significant performance improvement. With the recent development, radar network has become an attractive platform for target tracking. In practice, the netted radars in DRNS are supposed to maximize their transmitting power to achieve better target tracking performance, which may be in contradiction with low probability of intercept (LPI). This paper investigates the problem of adaptive resource scheduling based on time difference of arrival (TDOA) cooperation for target tracking by DRNS consisting of a dedicated radar netting station and multiple netted radars. Firstly, the standard interacting multiple model (IMM) algorithm incorporating extended Kalman filter (EKF) is improved by modifying the Markov transition probability with current measurements. Then, a novel resource scheduling strategy based on TDOA cooperation is presented, in which the LPI perfor¬mance for target tracking in DRNS is improved by optimiz¬ing the radar revisit interval and the transmitted power for a predefined target tracking accuracy. The comparison of the predictive error covariance matrix and the expected error covariance matrix is utilized to control the radar netting station under intermittent-working state with TDOA cooperation. Due to the lack of analytical closed-form expression for receiver operating characteristics (ROC), we utilize several popular information-theoretic criteria, namely, Bhattacharyya distance, Kullback-Leibler (KL) divergence, J-divergence, and mutual information (MI) as the metrics for target detection performance in target tracking process. The resulting optimization problems which are associated with different information-theoretic criteria are unified under a common framework. The non¬linear programming (NP) based genetic algorithm (GA) or else known as NPGA is employed to encounter with the highly nonconvex and nonlinear optimization problems in the framework. Numerical results demonstrate t

Projektpartner: Bundesamt für Lebensmittelsicherheit und Veterinärwesen BLV (EDI), 3003 Bern, Agroscope, Institut für Nutztierwissenschaften, 8356 Ettenhausen, Intellion AG, 9016 St. Gallen, Das Lokalisieren und Tracking von Objekten gewinnt auch für Indoor-Anwendungen immer mehr an Bedeutung. Eine vielversprechende Funktechnologie für echtzeit-basierte Lokalisierungssysteme (RTLS) ist die Ultra-Breitband-Technologie (UWB). Für die Lokalisierung in einem Stall von Agroscope wurde ein auf Time-Difference-of- Arrival (TDoA) basierendes Lokalisierungssystem entwickelt, das gleichzeitig bis zu 100 Tags im Sekundentakt und in Echtzeit lokalisieren kann. Mit TDoA lässt sich ein energie-sparendes und skalierbares RTLS realisieren. Die Tags senden dabei im Sekundentakt zu einem zufällig ausgewählten Zeitpunkt einen ultrakurzen Puls aus, der von vier oder mehr fix installierten und per Kabel miteinander synchronisierten Empfängern empfangen wird. Die Empfänger senden über Kabel die präzise Ankunftszeit an eine zentrale Einheit, wo mit der entwickelten Lokalisierungssoftware aus den Laufzeitunterschieden zu den einzelnen Empfängern die Position des Tags im Raum berechnet und angezeigt wird. In Feldtests konnte mit Verifikationsmessungen gezeigt werden, dass sich unter realen Bedingungen im gesamten Raum von 13m x 23m in 95% eine Lokalisierungsgenauigkeit von besser als 50cm realisieren lässt. Die Kollisionsrate betrug dabei <11%. Das hier entwickelte UWB-basierte Lokalisierungssystem lässt sich auch für das asset-tracking in der Produktion oder Logistik einsetzen.

Underwater source localization problems are complicated and challenging: a) the sound propagation speed is often unknown and the unpredictable ocean current might lead to the uncertainties of sensor parameters (i.e. position and velocity); b) the underwater acoustic signal travels much slower than the radio one in terrestrial environments, thus resulting into a significantly severe Doppler effect; c) energy-efficient techniques are urgently required and hence in favour of the design with a low computational complexity. Considering these issues, we propose a simple and efficient underwater source localization approach based on time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements, which copes with unknown propagation speed and sensor parameter errors. The proposed method mitigates the impact of the Doppler effect for accurately inferring the source parameters (i.e. position and velocity). The Cramér-Rao lower bounds (CRLBs) for this kind of localization are derived and, moreover, the analytical study shows that our method can yield the performance that is very close to the CRLB, particularly under small noise. The numerical results not only confirm the above conclusions but also show that our method outperforms other competing approaches., Signal Processing Systems

In the paper a mathematical model of a short-base multistatic system using aircraft transponder signals is presented. Several system modifications, combining a hyperbolic TDOA system, elliptical system using its own interrogator, angle measurement system and system exploiting the altitude information from the aircraft are simulated and analyzed. Their horizontal and vertical position estimation RMS errors are compared and possibilities of ADS-B based positioning system reliability enhancement are proposed., V práci je prezentován matematický model krátkodobého multistatického systému, který využívá signály transpondérů letadel. Několik modifikací systému, které kombinují hyperbolický systém TDOA, eliptický systém s vlastním dotazovačem, systém měření úhlu a systém využívající informace o nadmořské výšce z letadla, jsou simulovány a analyzovány. Jejich horizontální a vertikální odhad chyby RMS jsou porovnávány a navrženy jsou možnosti rozšíření spolehlivosti polohovacího systému založené na ADS-B.

This paper deals with estimation of time difference of arrival (TDOA) and phase and frequency offsets between the channels in a receiving system with two distributed time synchronized, but phase and frequency unlocked channels. The system receives a radio signal with a known waveform. We analyze the impacts of using the carrier phase of arrival (CPOA) on parameter estimation accuracy. Depending on which of the parameters are unknown, three cases are considered. For the case when phase, frequency, and time shifts are all unknown, we derive the Fisher Information Matrix (FIM) in closed form, and Cramer-Rao bound (CRB) closed form expressions for the unknown phase and frequency offsets case, and the unknown TDOA case. Two maximum likelihood type (ML) statistically efficient estimation algorithms are proposed. The CRBs and simulation results show that in the unknown TDOA case the accuracy of TDOA estimation can be significantly increased by using CPOA.

This paper deals with estimation of time difference of arrival (TDOA) and phase and frequency offsets between the channels in a receiving system with two distributed time synchronized, but phase and frequency unlocked channels. The system receives a radio signal with a known waveform. We analyze the impacts of using the carrier phase of arrival (CPOA) on parameter estimation accuracy. Depending on which of the parameters are unknown, three cases are considered. For the case when phase, frequency, and time shifts are all unknown, we derive the Fisher Information Matrix (FIM) in closed form, and Cramer-Rao bound (CRB) closed form expressions for the unknown phase and frequency offsets case, and the unknown TDOA case. Two maximum likelihood type (ML) statistically efficient estimation algorithms are proposed. The CRBs and simulation results show that in the unknown TDOA case the accuracy of TDOA estimation can be significantly increased by using CPOA.

This paper deals with estimation of time difference of arrival (TDOA) and phase and frequency offsets between the channels in a receiving system with two distributed time synchronized, but phase and frequency unlocked channels. The system receives a radio signal with a known waveform. We analyze the impacts of using the carrier phase of arrival (CPOA) on parameter estimation accuracy. Depending on which of the parameters are unknown, three cases are considered. For the case when phase, frequency, and time shifts are all unknown, we derive the Fisher Information Matrix (FIM) in closed form, and Cramer-Rao bound (CRB) closed form expressions for the unknown phase and frequency offsets case, and the unknown TDOA case. Two maximum likelihood type (ML) statistically efficient estimation algorithms are proposed. The CRBs and simulation results show that in the unknown TDOA case the accuracy of TDOA estimation can be significantly increased by using CPOA.

This paper deals with estimation of time difference of arrival (TDOA) and phase and frequency offsets between the channels in a receiving system with two distributed time synchronized, but phase and frequency unlocked channels. The system receives a radio signal with a known waveform. We analyze the impacts of using the carrier phase of arrival (CPOA) on parameter estimation accuracy. Depending on which of the parameters are unknown, three cases are considered. For the case when phase, frequency, and time shifts are all unknown, we derive the Fisher Information Matrix (FIM) in closed form, and Cramer-Rao bound (CRB) closed form expressions for the unknown phase and frequency offsets case, and the unknown TDOA case. Two maximum likelihood type (ML) statistically efficient estimation algorithms are proposed. The CRBs and simulation results show that in the unknown TDOA case the accuracy of TDOA estimation can be significantly increased by using CPOA.

Wide Area Measurements (WAMs) have been widely used in the energy management system (EMS) of power system for monitoring, operation and control. In recent years, the advent of synchronized Phasor Measurements Unit (PMU) has added another dimension to the field of wide-area measurement. However, the high cost of the PMU, which includes the manufacture and deployment fee, is a hurdle to the wide use of the PMU in power systems. Unlike traditional PMUs, the frequency monitoring network (FNET) developed by the Virginia Tech Power IT lab is an Internet—based, GPS—synchronized, wide-area frequency monitoring network deployed at the distribution level, providing a low-cost and easily deployable WAMs solution. In this dissertation, the research work can be categorized into two parts: FNET Design and Situation Awareness Algorithm Development.

Power transformers are one of the most important components in the electrical energy network. Extending transformer life is very economically valuable due to power outage. Therefore the development of instruments to monitor the transformer condition is of great interest. Detection of partial discharges (PDs) in power transformers is an effective diagnostic because it may reveal and quantify an important aging factor and provide information on the condition of the transformer. However, partial discharge diagnostics are still not effectively used for online monitoring of transformers because of the complexity of PD measurements and difficulties of discriminating of PDs and other noise sources. This thesis presents a further study of detection and location of partial discharges in power transformers based on previous work conducted at the Center for Photonics Technology (CPT) at Virginia Tech. The detection and positioning system consists of multiple extrinsic Fabry-Parot interferometric (EFPI) fiber acoustic sensors which can survive the harsh environment of oil-filled transformers. This thesis work is focused on optimal arrangement of multiple sensors to monitor and locate PD activities in a power transformer. This includes the following aspects. First, the sensor design requirements are discussed in order to successfully detect and accurately position the PD sources. In the following sections, Finite Element Method (FEM) is used to model the EFPI sensor fabricated at CPT. Experiments were conducted to measure the angular dependence of the frequency response of the sensor. It is shown that within the range of ±45º incident angles, the sensitivity varies by 3-5dB. Finally, the thesis demonstrates a PD positioning experiment in a 500 gallon water tank (R à H = 74" à 30" cylinder) using a hyperbolic positioning algorithm and time difference of arrival (TDOA). Finally we demonstrated that 100% of the positioning data is bounded by a 22.7à 4.1à 5.3 mm₃ cube, with a sensi

A partial discharge (PD) is the dissipation of energy caused by the buildup of localized electric field intensity. In high voltage devices such as transformers, this buildup of charge and its release can be symptomatic of problems associated with aging, such as floating components and insulation breakdown. This is why PD detection is used in power systems to monitor the state of health of high voltage transformers. If such problems are not detected and repaired, the strength and frequency of PDs increases and eventually leads to the catastrophic failure of the transformer, which can cause external equipment damage, fires and loss of revenue due to an unscheduled outage. Reliable online PD detection is a critical need for power companies to improve personnel safety and decrease the potential for loss of service. The PD phenomenon is manifested in a variety of physically observable signals including electric and acoustic pulses and is currently detected using a host of exterior measurement techniques. These techniques include electrical lead tapping and piezoelectric transducer (PZT) based acoustic detection. Many modern systems use a combination of these techniques because electrical detection is an older and proven technology and acoustic detection allows for the source to be located when several sensors are mounted to the exterior of the tank. However, if an acoustic sensor could be placed inside the tank, not only would acoustic detection be easier due to the increased signal amplitude and elimination of multipath interference, but positioning could also be performed with more accuracy in a shorter time. This thesis presents a fiber optic acoustic sensing system design that can be used to detect and locate PD sources within a high voltage transformer. The system is based on an optical acoustic (OA) sensor that is capable of surviving the harsh environment of the transformer interior while not compromising the transformer's functionality, which allows for online de

A partial discharge (PD) is the dissipation of energy caused by the buildup of localized electric field intensity. In high voltage devices such as transformers, this buildup of charge and its release can be symptomatic of problems associated with aging, such as floating components and insulation breakdown. This is why PD detection is used in power systems to monitor the state of health of high voltage transformers. If such problems are not detected and repaired, the strength and frequency of PDs increases and eventually leads to the catastrophic failure of the transformer, which can cause external equipment damage, fires and loss of revenue due to an unscheduled outage. Reliable online PD detection is a critical need for power companies to improve personnel safety and decrease the potential for loss of service. The PD phenomenon is manifested in a variety of physically observable signals including electric and acoustic pulses and is currently detected using a host of exterior measurement techniques. These techniques include electrical lead tapping and piezoelectric transducer (PZT) based acoustic detection. Many modern systems use a combination of these techniques because electrical detection is an older and proven technology and acoustic detection allows for the source to be located when several sensors are mounted to the exterior of the tank. However, if an acoustic sensor could be placed inside the tank, not only would acoustic detection be easier due to the increased signal amplitude and elimination of multipath interference, but positioning could also be performed with more accuracy in a shorter time. This thesis presents a fiber optic acoustic sensing system design that can be used to detect and locate PD sources within a high voltage transformer. The system is based on an optical acoustic (OA) sensor that is capable of surviving the harsh environment of the transformer interior while not compromising the transformer's functionality, which allows for online de

Tato diplomová práce se zabývá detekcí směru přicházejícího zvuku pomocí analýzy zvuku v malých mikrofonních polích. Využívá metod založených na časovém zpoždění signálu, dále na energickém poklesu či rozdílné fáze signálu. Práce se zaměřuje na zjišťování úhlu pomocí malých časových diferencích signálu. V závěru jsou shrnuty výsledky měření určování směru zvuku nahraného laboratorních podmínkách a reálném prostředí. Veškeré výpočty byly provedeny pomocí simulačního prostředí Matlab., This thesis describe detection of direction receiving sound with small–size microphone array. Work is based on analyzing methods of time delay estimation, energy decay or phase difference signal. Work focus mainly on finding of angle of arrival in small time difference. Results of measuring, as programming sound, so sound recorded in laboratory conditions and real enviroment, are mentioned in conclusion. All calculations were done by platform Matlab

Tato diplomová práce se zabývá detekcí směru přicházejícího zvuku pomocí analýzy zvuku v malých mikrofonních polích. Využívá metod založených na časovém zpoždění signálu, dále na energickém poklesu či rozdílné fáze signálu. Práce se zaměřuje na zjišťování úhlu pomocí malých časových diferencích signálu. V závěru jsou shrnuty výsledky měření určování směru zvuku nahraného laboratorních podmínkách a reálném prostředí. Veškeré výpočty byly provedeny pomocí simulačního prostředí Matlab., This thesis describe detection of direction receiving sound with small–size microphone array. Work is based on analyzing methods of time delay estimation, energy decay or phase difference signal. Work focus mainly on finding of angle of arrival in small time difference. Results of measuring, as programming sound, so sound recorded in laboratory conditions and real enviroment, are mentioned in conclusion. All calculations were done by platform Matlab

In this research, a novel approach for conducting signals intelligence from a distributed network of wireless nodes is developed. The primary objective of this research is enhancing signal collection in a specified target direction. Two conflicting priorities are addressed. One is the time required to determine the target direction and form the beams. The other is the energy consumption involved in developing these solutions. Two competing enhanced collection methodologies (ECM), ECM-1 and ECM-2, were developed and analyzed. ECM-1 uses a combination of time difference of arrival (TDOA) and adaptive beamforming. ECM-2 uses adaptive beamforming that performs a beamscan similar to phased-array radars. Additionally, two competing methods for forming the beams are developed. Method One uses data exclusively from the same elements. Method Two uses data from a new subset of sensors, for each iteration. Analytical expressions were derived for energy consumption and the time required to develop, to compare the competing methodologies. ECM-1 is shown to be far superior to ECM-2 in both energy consumption and the time required to enhance signal collection, whereas Method Two is shown to be far superior to Method One in formation of the beams., http://archive.org/details/enhancedradiofre1094510236, Approved for public release; distribution is unlimited.

Tato diplomová práce se zabývá detekcí směru přicházejícího zvuku pomocí analýzy zvuku v malých mikrofonních polích. Využívá metod založených na časovém zpoždění signálu, dále na energickém poklesu či rozdílné fáze signálu. Práce se zaměřuje na zjišťování úhlu pomocí malých časových diferencích signálu. V závěru jsou shrnuty výsledky měření určování směru zvuku nahraného laboratorních podmínkách a reálném prostředí. Veškeré výpočty byly provedeny pomocí simulačního prostředí Matlab., This thesis describe detection of direction receiving sound with small–size microphone array. Work is based on analyzing methods of time delay estimation, energy decay or phase difference signal. Work focus mainly on finding of angle of arrival in small time difference. Results of measuring, as programming sound, so sound recorded in laboratory conditions and real enviroment, are mentioned in conclusion. All calculations were done by platform Matlab

Tato diplomová práce se zabývá detekcí směru přicházejícího zvuku pomocí analýzy zvuku v malých mikrofonních polích. Využívá metod založených na časovém zpoždění signálu, dále na energickém poklesu či rozdílné fáze signálu. Práce se zaměřuje na zjišťování úhlu pomocí malých časových diferencích signálu. V závěru jsou shrnuty výsledky měření určování směru zvuku nahraného laboratorních podmínkách a reálném prostředí. Veškeré výpočty byly provedeny pomocí simulačního prostředí Matlab., This thesis describe detection of direction receiving sound with small–size microphone array. Work is based on analyzing methods of time delay estimation, energy decay or phase difference signal. Work focus mainly on finding of angle of arrival in small time difference. Results of measuring, as programming sound, so sound recorded in laboratory conditions and real enviroment, are mentioned in conclusion. All calculations were done by platform Matlab

Tato diplomová práce se zabývá detekcí směru přicházejícího zvuku pomocí analýzy zvuku v malých mikrofonních polích. Využívá metod založených na časovém zpoždění signálu, dále na energickém poklesu či rozdílné fáze signálu. Práce se zaměřuje na zjišťování úhlu pomocí malých časových diferencích signálu. V závěru jsou shrnuty výsledky měření určování směru zvuku nahraného laboratorních podmínkách a reálném prostředí. Veškeré výpočty byly provedeny pomocí simulačního prostředí Matlab., This thesis describe detection of direction receiving sound with small–size microphone array. Work is based on analyzing methods of time delay estimation, energy decay or phase difference signal. Work focus mainly on finding of angle of arrival in small time difference. Results of measuring, as programming sound, so sound recorded in laboratory conditions and real enviroment, are mentioned in conclusion. All calculations were done by platform Matlab

Tato diplomová práce se zabývá detekcí směru přicházejícího zvuku pomocí analýzy zvuku v malých mikrofonních polích. Využívá metod založených na časovém zpoždění signálu, dále na energickém poklesu či rozdílné fáze signálu. Práce se zaměřuje na zjišťování úhlu pomocí malých časových diferencích signálu. V závěru jsou shrnuty výsledky měření určování směru zvuku nahraného laboratorních podmínkách a reálném prostředí. Veškeré výpočty byly provedeny pomocí simulačního prostředí Matlab., This thesis describe detection of direction receiving sound with small–size microphone array. Work is based on analyzing methods of time delay estimation, energy decay or phase difference signal. Work focus mainly on finding of angle of arrival in small time difference. Results of measuring, as programming sound, so sound recorded in laboratory conditions and real enviroment, are mentioned in conclusion. All calculations were done by platform Matlab